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radiation heat flux
Posted Nov 20, 2009, 11:25 a.m. EST 3 Replies
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Hi
I have a question for radiation heat flux. I am trying to calculate radiation heat
transfer from surface to surface. I made a simple model and set the boundaries
heat flux with surface-to-surface radiation, temperature or insulated. Then I
use "postinterp" function to get radiation flux data. But all numbers are
"NAN". When I go through file->Export->Postprocessing Data, again I see some of
them "NAN". I am guessing it should be `0' not NAN for insulated or temperature
boundaries. I am using following format:
flux = postinterp(fem,'rflux_htgh',[x ;y ;z])
x,y,z vectors are coordinates for nodes.
I always use postinterp function (for convective and conductive simulations) to get my temperature or total heat flux data, but I am having problem with radiation heat flux. How should use this function to get radiation heat flux? Thank you for your suggestions.
Serap
I have a question for radiation heat flux. I am trying to calculate radiation heat
transfer from surface to surface. I made a simple model and set the boundaries
heat flux with surface-to-surface radiation, temperature or insulated. Then I
use "postinterp" function to get radiation flux data. But all numbers are
"NAN". When I go through file->Export->Postprocessing Data, again I see some of
them "NAN". I am guessing it should be `0' not NAN for insulated or temperature
boundaries. I am using following format:
flux = postinterp(fem,'rflux_htgh',[x ;y ;z])
x,y,z vectors are coordinates for nodes.
I always use postinterp function (for convective and conductive simulations) to get my temperature or total heat flux data, but I am having problem with radiation heat flux. How should use this function to get radiation heat flux? Thank you for your suggestions.
Serap
3 Replies Last Post Nov 27, 2009, 3:37 p.m. EST
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Posted:
1 decade ago
Hi
I agree NaN is not as I would expected either, If I take the model case HT Tutorail Model Cavity Radiation, there is no NaN in the File Export Postprocessed data, neiter for the subdomains, nor for the boundaries.
Ivar
I agree NaN is not as I would expected either, If I take the model case HT Tutorail Model Cavity Radiation, there is no NaN in the File Export Postprocessed data, neiter for the subdomains, nor for the boundaries.
Ivar
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Posted:
1 decade ago
Hi
Thank you so much for your answer. I tried HT Tutorial Model Cavity Radiation and I received some of them “NaN”. I tried in other computer and still I received “NaN”. I am using Comsol3.3a. Do you think this version have some bugs? I attached some pictures also. Thank you for your help and time.
The process I am following is:
1) Run the model
2) File -> Export-> PostProcessing Data
3) Then I select Boundaries from “Export Data From” section
4) From Boundary submenu, I select
a. Predefined quantities : Radiative flux
b. Expression : rflux_htgh
c. Unit : W/m2
Serap
Thank you so much for your answer. I tried HT Tutorial Model Cavity Radiation and I received some of them “NaN”. I tried in other computer and still I received “NaN”. I am using Comsol3.3a. Do you think this version have some bugs? I attached some pictures also. Thank you for your help and time.
The process I am following is:
1) Run the model
2) File -> Export-> PostProcessing Data
3) Then I select Boundaries from “Export Data From” section
4) From Boundary submenu, I select
a. Predefined quantities : Radiative flux
b. Expression : rflux_htgh
c. Unit : W/m2
Serap
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Posted:
1 decade ago
Hi
I'm running V3.5a,
I agree I get about 300 times NaN for the radiation flux, but when you check their coordinates you see they are the exteriour boundaries, not those inside the cavity.
Therefore I expect them to be NaN as they are not defined as "radiative", would'nt you too ?
Good luck
Ivar
I'm running V3.5a,
I agree I get about 300 times NaN for the radiation flux, but when you check their coordinates you see they are the exteriour boundaries, not those inside the cavity.
Therefore I expect them to be NaN as they are not defined as "radiative", would'nt you too ?
Good luck
Ivar